In the late 1920s, after leaving the Marines, James Gene Tunney (1897-1978) became a world heavyweight boxing champions, defeating Jack Dempsey in a celebrated match. Retired from boxing he went on to author two books and became a prominant businessman. Tunney's boxing gloves from the Tunney Dempsey fight can be viewed at the Smithsonian.

English bulldog Jiggs II was Tunney's own dog, donated to the Marine corp when Sergeant Major Jiggs I died in 1927. Bulldogs were adopted as the Marine dog during World War I. Since the enemy referred to U.S. Marines as "devil dogs," it seemed only fitting for recruitment posters to incorporate a tough, snarling dog wearing a Marine Corps helmet. A bulldog was chosen because the breed has the perseverence and toughness of a Marine. The first live bulldog to join the Marine Corps was King Bulwark, in 1922, renamed Jiggs and enlisted as a Private. Within a couple years Jiggs was promoted several times and achieved the rank of Sergeant Major.

Jiggs II only had the position for a year before dying of heat stroke, during which time he bit, chased and disrespected superiors.